Field
Exemplary embodiments of the present disclosure relate to extrusion of plastic batches, and more particularly to a device and method for overcoming the problem of bow in a honeycomb extrudate.
Discussion of the Background
Ceramic honeycombs for gasoline and diesel exhaust treatment applications can be produced by cutting and firing individual pieces from a stream of honeycomb extrudate, or by cutting the pieces from a dried green or fired ceramic “log” of extrudate which may be of meter or greater length. To meet customer requirements for the subsequent catalyst coating and “canning” of these ceramic honeycombs in suitable metal enclosures, it is important that the logs and pieces cut from the logs have sides which are straight and parallel.
The production of a straight stream of extruded material can be difficult; in most cases at least some “bowing” of the extrudate, attributable to uneven flow of material through the extrusion die, is observed. This bowing can be caused by non-uniform flow characteristics in the batch, but more commonly is due to uneven flow resistance across the face of the extrusion die. Even with careful attention to die fabrication, uneven machining resulting from facts such as progressive tool wear, misalignment of feed holes and discharge slots, and non-uniform exposure to chemical machining and/or plating electrolytes can result in at least some bowing tendency being “built in” to most honeycomb extrusion dies during manufacture.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.